1. Field of the Invention
The present invention generally relates to a shock-resistant arrangement for, and a method of, protecting a heat source from damage, especially for use in a color image projection system in which heat-generating lasers are used for projecting a two-dimensional image in color on a viewing surface away from the system.
2. Description of the Related Art
It is generally known to project a two-dimensional image on a screen based on a pair of scan mirrors which oscillate in mutually orthogonal directions to scan a laser beam over a raster pattern. However, the known image projection systems project the image with limited resolution, typically less than a fourth of video-graphics-array (VGA) quality of 640×480 pixels, and not in true color.
To obtain a true color image, red, blue and green laser beams emitted by lasers are needed. The red and blue lasers are semiconductor lasers and, when energized, produce their respective laser beams with concomitant generation of waste heat, which is typically readily dissipated to their common support and to the ambient environment. The currently available green laser, however, is not a semiconductor laser, but instead, is typically a laser module having an infrared diode-pumped YAG crystal laser and a non-linear frequency doubling crystal, whose operation produces a much greater amount of waste heat which must be aggressively transferred to the environment to prevent overheating. Indeed, a thermoelectric cooler is typically used to cool the green laser module, but the cooler also gives off heat which must be removed to prevent the cooler from overheating.
A heatsink is often used in the art to remove such heat. The heatsink is directly attached to the heat source in order to conduct heat therefrom. A problem arises, however, when the heat source is delicate, i.e., small and fragile, but nevertheless generates a great deal of heat, thereby requiring a heavy heatsink of large mass to remove the heat. A large heatsink rigidly attached to a delicate device, such as the aforementioned cooler, could cause failure of the device during a drop event, for example, if the system is implemented in a handheld instrument and is accidentally dropped to the floor. The cooler could crack, and the laser module attached to the cooler, could be moved out of optical alignment, thereby degrading the projected image.